The proposed research was designed in an effort to (1) detect and study the neoantigens of tumors of mice and man, (2) detect the presence and determine the frequency of cell-bound immunity and/or blocking antibodies to these tumors, and (3) attempt to modify the host immune response toward these neoantigens in an effort to impede tumor growth. A modification of the in vitro mixed leukocyte reaction has been used in these studies. At the present time the following tumors of mice are under study: B16, a melenoma; C3HBA, an adanocarcinoma; SAD2, a methyl cholanthrene induced sarcoma; MOPC-104E, a myeloma; and the lymphoma of Akr mice.